1. Field of the Invention
This invention relates generally to the field of working platforms and scaffolds. More specifically it relates to a working platform which allows for the adjustable attachment of scaffolds and the adjustable attachment of various platform leg members.
2. Description of the Prior Art
Scaffolds are used for a variety of purposes in the building construction and maintenance trades, such as painting, plastering, electrical, masonry, carpentry, etc. Once erected, scaffolds are difficult to move throughout a job site without disassembly. U.S. Pat. No. 2,360,999 to Wyen, attempted to solve this problem by adding rollers on the bottom of the scaffolds. Although the scaffolds can be rolled from location to location within the job site, the ground on which the scaffolds are rolled has to be relatively flat for the scaffold to properly roll such as interiors of concrete warehouses, for example. When the device is used on uneven surfaces, such as rough excavated ground surfaces, it becomes difficult to maintain a safe foundation for use of the device. The Wyen device also requires the scaffolds to be lifted off the rollers by using jack screws when a desired position is located.
Another device, shown in U.S. Pat. No. 4,216,933 to Cramer, shows a similar scaffold platform, but it too has deficiencies in its leveling process. Its vertical leveling corner supports require either a forklift, or similar piece of lifting machinery or actual man power to lift the platform to an elevation suited for use. The rigid vertical supports on this device have pre-drilled/pre-measured holes, where a pin is inserted for final adjustment. This requires the user to occasionally level the loose ground or use a leveling block under one or several of the corner supports. This arrangement could create a safety hazard to the overall stability of the unit if one or more of the leveling blocks would move or slide from under one of the vertical supports during usage.
The most common solution for mobility is to provide for an easily disassembled scaffold. An example of such a device is shown in U.S. Pat. No. 650,900 to Knopfe. This device is made of simple and interchangeable parts adapted to be quickly assembled and disassembled for transportation and movement within a job site. This unit uses adjusting shoes attached to the lower base beams for leveling on uneven surfaces. U.S. Pat. No. 3,071,204 to Piltingsrud also has adjustable legs as well as a variable length. Other mobility solutions but limited, are shown in U.S. Pat. No. 3,480,110 to Coleman and U.S. Pat. No. 3,850,264 to Salinas. In both designs, the devices provide for horizontal members extended from the main scaffolds on which a second platform is constructed. Instead of moving the scaffolds, they are extended. Both designs also have adjustable supporting legs and use a disassembly method for major mobility when in use.
Many of the above mentioned designs have adjustable supporting legs and some have extended horizontal members. Some of these designs use a disassembly method of the scaffolds for mobility purposes. The present invention will allow its unit to be moved while scaffolds are erected, together with tools and material being stored on the working platform, along with the safety side rails installed. This will allow the user to not only move the scaffolds without disassembly but also transport the tools and material needed for the job at hand.
While the prior art patents mentioned earlier offer some form of leveling support legs, the present invention utilizes screw type leveling jacks which allow exact leveling without the need for filler blocks which are required with the pre-drilled designs. Although several of the designs offer removable supporting legs, they are limited to only a few positions in which the supporting legs and supports can be positioned. This could cause difficult placement of the scaffold to a building or object when close confinement is inevitable. The present invention offers two positions for its screw jack bracket.
None of the prior art patents teach or suggest a movable scaffold base member to allow an in/out and circular side by side movement in their scaffold bases. The prior art devices are limited and can only be used with certain scaffolds offered in today's market due to size and adjustment confinements in accepting the vertical scaffold legs. The present invention offers an adjustable scaffold base allowing the majority of all scaffold designs which are using a four vertical leg support design to be used.
Without the supporting floor and safety rails, none of the previous mentioned patents can be used as an independent movable working platform, whereas this invention provides a safe and structurally secure working platform.